In recent years, disc-type brakes for vehicles have increasingly supplanted the previously conventional drum-type vehicle brakes.
In accordance with the present invention, a disc brake is provided which incorporates the functions, into one brake, of both the normal service brake, that is, the hydraulically actuated brake used to stop a vehicle, and a manual system, either for emergency or parking brake functions. The service brake is hydraulically actuated from a conventional automotive master cylinder plumbed to an hydraulic cylinder incorporated in the brake. The brake can also be actuated manually, independently of the hydraulic system, by lever or pedal structure remotely attached on the brake. This manual structure may be either for emergency situations or for parking.
Brake actuation is provided by hydraulically or manually rotating a central plate which, through a roller/ramp structure, moves a piston structure to engage both halves of the brake simultaneously, the brake incorporating two separate stacks of brake discs. The roller/ramp structure attenuates the hydraulic or manual force required to actuate the brake and, in effect, makes the brake operate as a self-contained power brake which may eliminate the need for a vacuum or power assist at the master cylinder. The pistons, rollers and central plate are held together by springs which return the pistons to a neutral position when hydraulic pressure or manual force is released. A roller/ramp structure is incorporated rather than a ball/ramp structure. This results in greatly reducing component stresses and simplifying machining.